Mineralised phytoplankton community composition in the Scotia and Weddell seas (Southern Ocean), with emphasis on diatoms and coccolithophores Amy Harington.

Phytoplankton community composition in the Southern Ocean (SO) determines levels of primary production, which support marine ecosystems and export of material to the deep sea. Nanoplankton (cell diameters 2-20 μm) are poorly resolved by traditional microscopy, and it is becoming apparent that unknown diversity and ecosystem functionality may be contained in this size class: for example, small diatoms (< 10 μm) appear widespread in the SO, and may limit our understanding of the response of phytoplankton communities to climate change.